So I go to replace a bad starter in my triple six.(the starter motor itself was toast)D312 with manual trans.I buy a replacement and double check to make sure it's the right one... part number crosses correctly and the starter is like for like.(something I always do)Rotates the right way,drive gear the same etc.Install starter hit the button and it grinds on the ring gear but doesn't engage.What the...so pull starter sure enough starter ground off top part of one tooth on ring gear.Recheck new starter again thought maybe starter drive travel dimensions were not the same,they were.Flange distance to ring gear was identical to old starter.Long story short had to use old starter drive flange,drive gear and bendix before it would work correctly.
Paul
Paul